1. Field of the Invention
The present invention relates to a device for holding down a valve for the metering of fuel in a cylinder head bore in the cylinder head of an internal combustion engine, which is plugged in, using a connection piece, to a sealing region pressing against the connection piece on an outlet opening of a manifold that is able to be fixed to the cylinder head for fuel supply.
2. Description of the Related Art
By “fuel,” one should understand in this connection a fluid, that is, liquid or gaseous fuel whose chemical energy is transformed by combustion in an internal combustion engine, such as an Otto engine, a Diesel engine or a gas engine into a driving force.
One known mounting support for a fuel injector on the cylinder head of an internal combustion engine, described in published German patent document DE 197 58 817 B4, has a spring element developed as a helical compression spring, which is clamped in between a first support shoulder developed on the valve and a second support shoulder developed on the fuel manifold and encloses the valve in such a way that a spring force in the direction of the longitudinal axis of the valve is able to be transferred to the valve. The support shoulders are developed as annular mountings and face each other in the mounted state. The fuel manifold has a connection piece for each valve, known also as a connecting cup, having a fuel outlet opening at the base. Into the connection piece an intermediate sleeve is installed that encloses the outlet opening in a sealing manner, and is fixed on the fuel manifold using a securing element that grasps the connection piece from the outside. The intermediate sleeve, within certain limits, permits a flexible connection of the outlet opening of the fuel manifold with the connection piece of the valve that dips into the intermediate sleeve. Between connection piece and intermediate sleeve a sealing ring has been inserted that presses against the connection piece.
During assembly, the spring element is pushed onto the intermediate sleeve, and the valve with its connection piece is pushed into the connection sleeve. As long as the spring element remains unstressed, the friction of the sealing ring is sufficient to hold the valve on the fuel manifold. The subassembly of valve and fuel manifold is mounted on the cylinder head in that the valve is set into the cylinder bore and the fuel manifold is pressed down until a holding piece that is on the fuel manifold makes contact with a holding base that projects from the cylinder head. Because of the great guidance length of the connection piece present in the intermediate sleeve, it is possible to compress the spring element from its unstressed position to such an extent that, upon contact of holding piece and holding base, the desired holding-down force is transferred axially to the valve. Using a cap screw guided through the holding piece, the fuel manifold is screwed down in the holding base.